Control of magnetic anisotropy by orbital hybridization in (La0.67Sr0.33MnO3)n/(SrTiO3)n superlattice

TL;DR

This study demonstrates how manipulating the periodic thickness in La0.67Sr0.33MnO3/SrTiO3 superlattices controls magnetic anisotropy through orbital hybridization and charge transfer at the interface, enabling tailored electronic and magnetic properties.

Contribution

It reveals the role of orbital hybridization and interfacial charge transfer in controlling magnetic anisotropy in oxide superlattices, a novel approach for material property engineering.

Findings

Magnetic easy axis switches from in-plane to out-of-plane with changing superlattice thickness.

Orbital hybridization favors 3d3z2-r2 orbital occupancy at the interface.

Interfacial charge transfer occurs from Mn to Ti 3d orbitals.

Abstract

The asymmetry of chemical nature at the hetero-structural interface offers an unique opportunity to design desirable electronic structure by controlling charge transfer and orbital hybridization across the interface. However, the control of hetero-interface remains a daunting task. Here, we report the modulation of interfacial coupling of (La0.67Sr0.33MnO3)n/(SrTiO3)n superlattices by manipulating the periodic thickness with n unit cells of SrTiO3 and n unit cells La0.67Sr0.33MnO3. The easy axis of magnetic anisotropy rotates from in-plane (n = 10) to out-of-plane (n = 2) orientation at 150 K. Transmission electron microscopy reveals enlarged tetragonal ratio > 1 with breaking of volume conservation around the (La0.67Sr0.33MnO3)n/(SrTiO3)n interface, and electronic charge transfer from Mn to Ti 3d orbitals across the interface. Orbital hybridization accompanying the charge transfer results in preferred occupancy of 3d3z2-r2 orbital at the interface, which induces a stronger electronic hopping integral along the out-of-plane direction and corresponding out-of-plane magnetic easy axis for n = 2. We demonstrate that interfacial orbital hybridization in superlattices of strongly correlated oxides may be a promising approach to tailor electronic and magnetic properties in device applications.